What’s On: ‘You’re the Worst’ returns, ‘I’m Sorry’ Finale, and a week-long marathon of ‘South Park’

Byron Cohen/FX
You're the Worst

A critical checklist of Wednesday’s TV:

You’re the Worst (10/9c, FXX): The fourth season of the ribald anti-romcom returns in the wake of the most severe split yet in the on-off (currently off) relationship of Jimmy (Chris Geere) and Gretchen (Aya Cash). Months have passed without a word from Jimmy, who’s gone off the grid since flipping out and abandoning his snarky soulmate. In the hourlong episode that resets the situation, we catch up with Jimmy’s rather sad existence as a mostly lone wolf among a demographic not his own—Raymond J. Barry and Dee Wallace give terrific guest performances—while Gretchen spirals in an agoraphobic funk in Lindsay’s (Kether Donohue) apartment. You know you’ve hit bottom when Lindsay and Edgar (Desmin Borges) are the voices of reason.

I’m Sorry (10/9c, truTV): Another comedy whose title sounds more like a lamentation is Andrea Savage’s wallow in social bad behavior. In the season finale—Sorry has already been renewed—Andrea and Mike (Tom Everett Scott) obsess about getting older, so as couples do, they conduct a spot check on their fertility. No need to apologize.

South Park (9 am/8c, Comedy Central): Here’s one way to count the hours until South Park returns for its 21st season next Wednesday: a non-stop weeklong marathon of all 254 episodes from past seasons, starting with the unforgettable “Cartman Gets an Anal Probe.” Only taking a break for the nightly installment of The Daily Show With Trevor Noah, Comedy Central devotes the rest of its schedule to Trey Parker and Matt Stone’s subversive classic.

Inside Wednesday TV: “I love the Internet,” Bill (Brendan Gleeson) grouses on AT&T Audience Network’s Mr. Mercedes (8/7c) as he engages in another round of mutual taunting with his unseen nemesis, Brady (Harry Treadaway). He doesn’t really mean it, but this time Bill strikes a nerve when he mocks the villain’s relationship with his mother (Kelly Lynch). If he only knew—emphasis on ewww. … The conclusion of History’s Road to 9/11 (9/8c) goes inside the planning and execution of the terror attacks and examines how the U.S. government failed to pick up warning signals because of a disconnect between agencies. … Andy Cohen sits with Real Housewives of New York City’s notoriously camera-shy (I kid!) Luann de Lesseps at her Sag Harbor manse for a special edition of Bravo’s subtly titled Watch What Happens Live with Luann de Lessups (11/10c) for the first time since announcing her divorce. Does this mean a Real Ex-Housewives spinoff?